Platteville, Wisconsin, sits in USDA hardiness zone 5a — a zone band wide enough that plant choice, not possibility, is the interesting question.
A short list that earns its place here — cabbage, cranberry, lavender, and collard greens — with any one site's soil, sun, and drainage making the final cut.
Even in Platteville, no two yards are alike.
A low spot, a south-facing slope, or a stand of trees moves the frost date and sun across a single Platteville lot. Enter your address and we'll score 1,086 plants against your land's actual soil, sun, and frost.
We read public map data around Platteville — soil, climate, flood, and parcel records. How we handle your address.
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Platteville — the short answer
Platteville, Wisconsin: USDA zone 5a, about 189 days between hard freezes, across 4K acres of city.
- USDA zone
- 5a
- USDA PHZM 2023
- Last hard freeze (28°F)
- Apr 15
- NOAA 1991–2020 Climate Normals, 28°F — this town
- First hard freeze (28°F)
- Oct 21
- NOAA 1991–2020 Climate Normals, 28°F — this town
- Days between freezes
- ~189
- NOAA 1991–2020 Climate Normals, 28°F — this town
- City area
- 4K acres
- US Census TIGER/Line 2025
Every figure names the dataset it came from. Hard-freeze dates are this town’s own 28°F normals: light frosts run a few weeks past them, and tender transplants usually wait 2–3 weeks after the last hard freeze.
Hardiness Zone Range
Zone 5a is Platteville's average, not your lot's — a low corner or a tree line moves it. Against Platteville's 189-day season, see what your own ground reads.
Soil varies lot by lot — soil types explained.
What this means for growing in Platteville
Each reading below is measured for Platteville itself — here is what it means for a garden here, and the move an experienced grower makes about it.
Season length
MeasuredPlatteville runs about 189 days between hard freezes — a moderate growing season.
There is room for the full run of cool-season crops plus a warm-season main crop, but the calendar is tight enough that a late spring or early fall frost still decides how much finishes.
Time warm-season transplants to your last hard freeze, and a few weeks of season extension turns a near-miss harvest into a sure one.
NOAA 1991–2020 Climate Normals
Winter hardiness
MeasuredPlatteville sits in USDA hardiness zone 5a.
The zone sets which perennials, shrubs, and fruit trees live through an average winter here — a plant rated for a colder zone is a safe bet, one rated warmer needs winter protection or gets treated as an annual.
Match perennials and fruit to the zone before you buy, so nothing you plant is a gamble against the cold.
USDA PHZM 2023
The kind of country Platteville is in
Platteville sits in the Driftless Area — EPA Level III, inside the wider Eastern Temperate Forests. That is read at Platteville's own centroid rather than borrowed from Grant County.
What Grows in Platteville
Every plant below cleared Platteville's own zone 5a and its 189-day season. Each card opens that plant's Wisconsin profile. How we score.
Is it too late to plant in Platteville?
Usually not — gardeners here simply switch what goes in the ground as the season moves. Cool-season crops can go in from around Mar 18; tender transplants wait until two to three weeks after the last 28°F hard freeze, which lands near Apr 15 (NOAA 1991–2020 climate normals); and from midsummer, planting counts back from the first fall freeze around Oct 21 — long-season crops need about 90 days of runway, quick greens only 30. As the window narrows, the plantings just get faster — fall brassicas, then greens, then garlic to finish.
What's on the federal record near Platteville
Closest first, within ~10 miles of Platteville. Listing isn't leaking, and distance isn't exposure.
- GR-03/01W/15-0023Nitrate · 1100 ft
- Platteville Consumers Oil Co OpUnderground Storage Tanks · 1200 ft
- Platteville City GarageUnderground Storage Tanks · 1200 ft
- New Horizons Supply CooperativeUnderground Storage Tanks · 1300 ft
- GR-03/01W/15-0022Nitrate · 1400 ft
- LARRY DROSSLER WHITE COUnderground Storage Tanks · 1400 ft
- Enterprise MineMining · 1400 ft
- Southwest Supply IncUnderground Storage Tanks · 1600 ft
- LAWINGER CONSTRUCTIONUnderground Storage Tanks · 1600 ft
- HARLEY'S CAR CARE & TOWINGUnderground Storage Tanks · 1700 ft
- FORMER LEIBFRIED FEED SERVICEUnderground Storage Tanks · 1700 ft
- EnterpriseMining · 1900 ft
6 more sites are on the record inside the same radius. See them on the map
Measured from Platteville's center, not your beds. Run your own address for what's upwind of you specifically.
Environmental Intelligence
The counts behind that headline — every source type on the record near Platteville.
Total Sites
422
within ~10 miles of Platteville
Risk Level
High
Highest-severity
1 Superfund site (none NPL-listed)
Sources Checked
within ~10 miles of Platteville
Severity Distribution
within ~10 miles of Platteville
Highest-Severity Sites
A note from Gnorman
What an experienced grower watches for around here
In and around Platteville, two things run higher than the national average within ~10 miles of Platteville — Mining (169 sites) and CAFO (4 sites). That's not a problem with your land — it's information about it.
Mining: Mining sites — both historic and active — can leach heavy metals (arsenic, lead, cadmium, mercury) into soil and water for centuries after operations cease.
CAFO: CAFOs pose a different contamination profile than chemical sources.
Test soil for heavy metals (lead, arsenic, cadmium, mercury) — this is essential near any mining site.
Wash all produce consumed raw thoroughly, especially leafy greens grown near CAFOs.
Check your specific parcel in Platteville
Get exact proximity distances to contamination sources for your specific parcel — plus soil, sun, drainage, and 1,086 plant recommendations.
25+ data sources read at your address, not the Platteville average
Your land is one point inside Platteville
Everything above resolves to Platteville as a whole — one PHZM band and one 28°F frost record, read across 4K acres. Your parcel is one point inside that footprint. Slope, tree cover, a low spot that pools cold air, and what is in the soil are all resolved at the address, and none of them are visible at city scale. That is the honest boundary of this page, and the reason the next step is a reading of your own ground rather than a better local average.
Your Lot vs the Platteville Average
Platteville Average
- ●USDA Zones 5a, averaged across Platteville
- ●One soil character for all of Platteville
- ●Frost dates read at Platteville's scale: Apr 15 to Oct 21
YOUR Parcel
- ✓Your exact zone, not Platteville's 5a
- ✓Your SSURGO soil type & pH
- ✓Your sun exposure, cast in 3D
See MY Growing Report
Read your specific parcel in Platteville
Pull a site-specific report for your exact address in Platteville, Wisconsin — soil, sun, drainage, frost risk, and scored plant recommendations.
Three things about your lot that Platteville averages can't show:
We read public map data around Platteville — soil, climate, flood, and parcel records. How we handle your address.
25+ data sources read at your address, not the Platteville average
How we know this about Platteville
The datasets: hardiness from the USDA ARS Plant Hardiness Zone Map 2023, read at this city’s own centroid; hard-freeze dates from NOAA 1991–2020 28°F normals at Platteville’s own record; boundaries and acreage from US Census TIGER/Line 2025; the contamination records from the federal sources named in their beats above. Soil is not read at city grain anywhere on this page — there is no city-resolution survey in our data, which is why you will find no soil grid here rather than a statewide one wearing a local label. The resolution ledger below names every figure this page inherited.
Common questions about Platteville
When does frost risk typically end in Platteville?
The last hard freeze (28°F) in Platteville typically lands around Apr 15, per NOAA 1991–2020 climate normals — earlier than the light-frost dates most charts quote. That marks the hard freeze, not the last light frost — lighter frosts keep biting past it, which is why tender transplants here wait until about May 6.
When is the first frost in Platteville?
The first hard freeze (28°F) in Platteville typically arrives around Oct 21, per NOAA 1991–2020 climate normals — the point tender summer crops finish. Lighter frosts run ahead of it, near Oct 7, so the watching starts about Sep 21 — about 189 days after the spring freeze cleared.
How long is the growing season in Platteville?
Measured between 28°F hard freezes, Platteville sees about 189 frost-free days — roughly Apr 15 through Oct 21, per NOAA 1991–2020 climate normals. Tender crops work a shorter one: nearer May 6 to Oct 7, about 154 days.
Is the soil safe to grow vegetables in Platteville?
The federal record around Platteville runs heavier than most — 422 documented sites, mostly Underground Storage Tanks entries (190), the nearest Nitrate record about 0.2 miles out — so test the soil before planting food in the ground, and raised beds with clean imported soil grow well in the meantime. Even here, proximity to a documented site is information, not a diagnosis of any one yard; the contamination map shows exactly what's recorded and where.
How do I protect my plants from frost in Platteville?
From about Sep 21 the job here turns from planting to protecting — the last start even a 30-day crop can finish. As the season closes around the first 28°F hard freeze near Oct 21 (NOAA 1991–2020 climate normals), three moves buy time: row cover or an old sheet over tender plants on still, clear nights; water the soil the afternoon before a freeze, so it holds warmth overnight; and harvest tomatoes, peppers and basil before Oct 21. Hardy greens and roots shrug off light frost and sweeten after it — leave them in.
Everything above is measured at Platteville's scale — its 5a band and its 189-day season. Your yard writes its own version of Platteville's numbers: we read soil, sun, drainage and frost at your exact address. Try it for 14 days — no card required.
What this page reads at Platteville’s own scale
6 of the readings below were taken at Platteville's own scale — its own ~189-day season between 28°F freezes, the 3,956 acres it covers and 422 documented sites around it; 4 are borrowed from a wider read, named and linked below.
Measured here
- Platteville's own USDA hardiness band, zones 5aUSDA PHZM 2023
- Platteville's own 28°F hard-freeze dates, about Apr 15 and Oct 21 and the ~189-day span between themNOAA 1991–2020 Climate Normals
- 422 documented contamination sites on the federal record near Platteville, the closest Nitrate record about 0.2 miles out from the town centreFederal environmental registers
- Platteville's boundary and the 3,956 acres inside itUS Census TIGER/Line 2025
- Which of 1,086 plants clear zones 5a and a ~189-day seasonGrowable Ground crop-matching engine
- The ecoregion at Platteville's own centroid, the Driftless AreaUS EPA Level III Ecoregions
Inherited from a wider read
- Soil character — no town-scale survey exists, so Platteville's 3,956 acres read through its county's SSURGO summaryfrom Grant County
- Growing-degree days and winter chill — measured county-wide only, so the county page carries themfrom Grant County
- The growing challenges every Wisconsin grower plans around — written at state scale, so they stay on the state guidefrom Wisconsin
- Butterfly and beetle records, and the farmland pesticide estimate — all published county-widefrom Grant County
What this page can’t tell you
- The soil pH, drainage, sun hours, and frost pockets on any one lot among Platteville's 3,956 acreswhy one lot differs from the next →
- Which side of Platteville you're on — a low spot frosts first and a south wall warms early, and one normal is being asked to speak for all 3,956 acresreading your own microclimate →
- How close that record sits to YOUR lot — the closest Nitrate record about 0.2 miles out, measured from the town centrehow we read the record →
- Where cold air settles, which slopes face the sun, and which way the wind runs on your own ground — measured at your address, and averaged away by any Platteville-wide figureread your own land →
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